Process of drying sodium-bisulfite crystals.



H. HOWARD. I PROCESS OFVDRYING SODIUM BISULFITE CRYSTALS.

APPLlCAT-ION FILED JUNE 24. 1913.

l; Patented May 11, 1915.

T @FFQE NETE@ STAEE@ PROCESS OF BRYING SGDIUIlVI-BISULFITE CRYSTALS.

Application led June 24. 1913.

To IN lc/iam 'it m n.1/ comer/1.:

lie it known that l, llnsnr llowanu, a citizen ol'v the United States, residing at Brookline, in the county ot' Norfolk and State ot' Massachusetts, have invented certain new and useful Improvements in lrocesses ot' Drying Sodium-lisuliite Crystals, ot' which the 'following is-a speciti ,ati( n.

When wet crystals ot' sodium bisultite, Nal"lb`(), are dried in an atmosphere ot air, they deconipose to a considerable extent, with evolution ot sulfur dioxid. A\ccording to the present invention, such\re:ulily-decom posable crystals are dried in an atmosphere ot the `:las which would be evolved by their decomposition. The process is preferably carried out by stirring the wet bisullite crystals within a closed steam-jacketcd chamber, passing a current ot' suliur dioxid through this chamber, and condensing and removing the moisture t'rom the etlluent gas and returning it to the dlying-chamber.

Suitable apparatus for carrying out the process is shown in the,accompanying drawing, in which the figure is i side elevation, the llryi11g-chamber and a gas-holder being shown in transverse section. '.Ihis dryingchamber l is a gas-tight cylindrical steamjacketed drum, having an inlet 2 tor the wet crystals :url an outlet for the dry crystals. .\u agitator l havingr radial stirring-arms is cimcentricall iournaled within this chamber. A pipe 5 lor supplying sultur dioxid leads into the chzuuber` and a pipe (3 t'or removing.r the moisture-buien gas leads from the top ot' the chamber to a condenser 7.

rl`he chamber l and condenser 'i' are main tained at suitable dill'crent temperatures, to occasion the requisite. dili'erence ot' aqueous vapor-pressi:res therein. From the condenser, a pipe H leads downward to a vessel S) in which the water is collected. 'lhe water-free gas thence passes through a pipe l() into .a gas-holder ll, l'rom which it is drawn by a pipe 1Q and pump 13 and forced through a pipe 1-t back to the drying-chamber. The, gas-holder may bcomitted.

Instead ot', or in addition to heating the crystals by steam, the sulfur dioxid or other Specification of Letters Patent.

Patented May 11., 1915.

Serial No. 775,608.

gas, after leaving the condenser, may be preheated betore it is returned to the dryingchamber, thereby serving as a heating medimn. Whatever the heating means employed, the use ot' an atmosphere of sulfur dioxid, or other gas which would result from the decomposition ot' the particular compound to be dried, a lt'ords proper conditions for the rapid removal ot' moisture from the heated mass.

The process is especially applicable to the drying ot' both sodium bisultite and rnetabisullite (Na,b`. crystals, both of which are included under the term sull'ite crystals, in the claims.

l. rl`he process of drying sulfite crystals, which consists in removing the moisture from said crystals in an atmosphere ot' sulfur dioxid.

2. The process ot' drying sulfite crystals, which consists in heating the wet crystals in a closed chamber, and passing a current of sulfur 'lioxid `cias through said chamber.

The process ot drying sultite crystals, which consists in heating the wet crystals in a closed chamber, and passing a current ot' hot suliur dioxitl gas through said chamber,

l. 'l`he process ot' drying suliite c: 'stals, which consists in heating and agitating the wet crystals in a closed chamber, passing a current ot' sult'ur dioxid gas through said chamber, and removing the moisture from the ellluent gas and returning it t0 said chamber.

5. 'lhe process ot drying sultite crystals, which consists iu heating aml agitating the wet crystals in a closed chamber, passing a current ot' hot sult'ur doxid gas through said chamber, and removing the moisture from the ellluent gas and returning` itto said chamber.

In testimony whereotl l atlix my signature in presence ot' two witnesses.

ll llNltY HOWARD.

Witnesses I. M. GRAHAM, M.. V. OBmnN. 

